Rugby union has emerged as the next stop for 23-year-old Folau after he turned down an offer to return to rugby league in the NRL with Parramatta last week, having quit his multi-million dollar AFL deal with Greater Western Sydney last month.

Labelled a cash-hungry mercenary in some quarters after walking away from protracted talks with Parramatta, Folau took to Twitter late on Sunday.

"Everyone is entitled to their opinions! But I'll speak the truth when it's my time," Folau tweeted.

That time may be as early as Tuesday or Wednesday, with speculation rife the former Kangaroos centre is poised to sign a one-year deal with the Waratahs.

Along with the Rebels, the 'Tahs are the only Australian franchises to have a spot to fill on their 30-man roster for next season.

But the Rebels, who were reportedly extremely close to signing Folau in 2010 before he moved to the AFL, on Monday shut the door on the possibility of recruiting the former Melbourne Storm and Brisbane Broncos centre.

"Israel is a rare talent and would be a great asset for rugby," said Hill.

"But I can't see how any Super Rugby clubs, including the Rebels, could afford him with the late timing and the salary caps that have been enforced."

That leaves the Tahs as the only viable option for the off-contract Folau, who struggled badly in AFL and left GWS admitting "the passion wasn't there."

A $4.5 million salary cap for each of Australia's five Super Rugby clubs has been introduced for the first time and takes effect from the start of next year as the Australian Rugby Union attempts to rein in player salaries.

Finding a spot for Folau in a Waratahs backline already flush with Wallabies outside backs would create a selection poser for new coach Michael Cheika.

But before he can even grapple with that dilemma, chief executive Jason Allen and Folau's manager Isaac Moses must first wrestle with the financial predicament.

The Waratahs are likely to have a minimal amount left in their kitty for next season to offer Folau, who was paid $1.5 million per season at GWS.

The Eels drew up a deal for Folau reportedly worth $3 million over four years.

Even if a slimmed down deal for next season can be agreed upon, the NRL's soon-to-be increased salary cap of around $5.2 million for 25 players is significantly more than Super Rugby's fiscal limitations.

But if Folau is to remain in Sydney, take on the challenge of a third football code and be remunerated handsomely, Waratahs fans can expect an overhaul of their squad at the end of 2013 to accommodate marquee man Folau.

A winger or centre in rugby league, Folau would likely slot into the outside backs where the 'Tahs already boast the likes of Wallabies Adam Ashley-Cooper, Drew Mitchell, Berrick Barnes, Rob Horne and Lachie Turner while impressive youngsters Bernard Foley and Tom Kingston as well as stalwart Tom Carter also complicate selection.